Given an m x n matrix mat where every row is sorted in strictly increasing order, return the smallest common element in all rows. If there is no common element, return -1. Example 1: Input: mat = [[1,2,3,4,5],[2,4,5,8,10],[3,5,7,9,11],[1,3,5,7,9]] Output: 5 Example 2: Input: mat = [[1,2,3],[2,3,4],[2,3,5]] Output: 2 Constraints: m == mat.length n == mat[i].length 1 <= m, n <= 500 1 <= mat[i][j] <= 104 mat[i] is sorted in strictly increasing order.